The shredding of scrapped vehicles for breaking down materials has been known for a long time. In carrying out the shredding process, process controls have been established in which the material mixture produced is divided up into different fractions. Thus, a so-called shredder light fraction (SLF) is initially separated from the material mixture produced, using a suitable suction device. The remaining fraction is subsequently separated into a ferromagnetic fraction (shredder scrap (SS)) and a non-ferromagnetic fraction (shredder heavy fraction (SHF)), using a permanent-magnet separator. The fraction of the metallurgically fully usable shredder scrap-metal fraction is often approximately 50 to 75 wt. %. Existing designs generally provide for the shredder light fraction being disposed of as waste or burned in waste incinerators. It is characterized by both a large fraction of organics and a large fraction of fine-grained material. The heavy fraction, which is not able to fly and is not ferromagnetic, i.e., the shredder heavy fraction, is distinguished by a large percentage of nonferrous (NF) metals. Special sorting systems have been developed for recovering the various NF metals, where, however, the remaining residue of organic and inorganic, non-metallic components is generally disposed of as waste. In the following, shredder residues should be understood as all material streams from the shredding process, which cannot be directly removed at the shredder as products that are metallurgically directly utilizable (shredder scrap).
Described in German Published Patent Application No. 44 37 852 is a method, in which the shredder light fraction is sorted, in particular to remove “unwanted components”, especially copper and glass. In this context, the shredder residues are homogenized and mixed in a compulsory mixer with a fine-grained to superfine-grained material containing a magnetizable component, and the resulting mixture is conveyed through a magnetic separator. In this context, it has been shown that the metallic components of the shredder light fraction, which impede metallurgical use, may be separated out in this manner.
European Published Patent Application No. 0 863 114 provides for the production of a permanently plastic, backfilling material for mines, by adding an adhesive component, a filler, and a salt solution to the shredder light fraction. This is intended to provide a pressure-resistant, permanently plastic body.
It is described in German Published Patent Application No. 197 42 214 that the shredder light fraction is shredded further and subjected to a thermal treatment. In this context, metallic components should be sorted out during or after shredding, and the remaining mixture of materials should be melted in a smelting reactor and converted to a “harmless” solid by cooling it.
In addition, European Published Patent Application No. 0 922 749 describes a method for processing the shredder light fraction, where the shredder light fraction is calcined in a fluidized-bed gasifier amid the introduction of or in the presence of calcium carbonate.
In a further, thermal process, German Published Patent Application No. 197 31 874 provides for the shredder light fraction being compressed again in a further step, and then shredded, homogenized, and reduced in water content, in order to be thermally utilized in a subsequent step.
European Published Patent Application No. 0 884 107 provides for the shredder light fraction being converted into a metal-free fraction having a shredding or grinding size of <20 mm, by shredding, classifying, and sorting it. The sorting of the shredder light fraction should result in a thermally utilizable fraction.
In addition to the utilization methods shown, it is conventional that the shredder light fraction can be subjected to a pretreatment, in which residual ferromagnetic fractions of iron, stainless steel, and aluminum are separated. Similar methods have also been used for sorting the shredder heavy fraction. Furthermore, it is conventional that polyolefins can be separated from this fraction.
What the shown methods have in common is, that they are each only designed for processing the shredder light fraction or the shredder heavy fraction. Not provided is common processing with the object of separating the shredder residues as much as possible into at least partially utilizable end products, in particular into a sand fraction which is utilizable as a raw material or can be landfilled in accordance with the current requirements from the German Technical Instructions on Waste from Human Settlements taking effect in a new form as of the year 2005. Against the background of increasing legal requirements (EU End of Life Vehicles Directive, EU Directive on Incineration of Waste, and others), as well as increasing landfill costs and requirements for the material to be landfilled (Technical Instructions on Waste from Human Settlements), an increased utilization rate and an optional pretreatment prior to storage in a landfill is, however, desirable. Thus, the German regulation on end of life vehicles of Apr. 1, 1998 provides for over 95 wt. % of a scrapped car having to be utilized as of the year 2015. In addition, increased requirements from the EU Scrapped Car Guideline passed in September, 2000 specify that the fraction of material streams utilizable as materials and raw materials for mechanical and feedstock recycling should be increased to at least 85 wt. %. Therefore, utilization excludes the mere use as energy, e.g., in waste-incineration plants, in which a disposable, inert fraction would be produced as a secondary effect. The emphasis of the Technical Instructions on Waste from Human Settlements to be observed as of the year 2005 is the requirement for decreasing the organic fraction and the elution potential of heavy metals of the fractions to be landfilled. To be able to use the produced sand fraction as a raw material, e.g., as a loading material or an aggregate in cement plants or sintering plants of blast-furnace factories, or in an aggregate for the manufacture of backing brick in brickkilns, it may be ensured, in particular, that disruptive heavy metals and organic components were removed to the greatest possible extent.
Therefore, an object of the present invention is to provide a method and the system necessary for it, by which shredder residues may be processed, and by which, in addition to further end products, a high-quality sand fraction usable as a raw material or at least disposable in a landfill for human-settlement waste in accordance with future standards, may be produced in a mechanical sorting process.